There are a number of reasons Steve Ballmer is retiring as CEO of Microsoft. But, the number one reason is what you see in this chart from Benedict Evans.
He missed out on the rise of mobile, which is altering the personal computer industry.
As soon as Apple released the iPad, global PC sales went flat, then started to decline. The iPad was enabled by the iPhone, which was a device Ballmer laughed at when it was released.
While PC sales have stalled, sales of iPhones and Android-based devices have exploded, which you can see here.
If Ballmer had successfully participated in this explosion in mobile devices, he would still be the CEO of Microsoft.
He says he’s retiring because he thinks now is a good time for a transition. We think that if Windows Phone were equal with iPhone and Android, he’d still be around, leading the company for a few more years.